erupt, break out -- (start abruptly; "After 1989, peace broke out in the former East Bloc")
erupt, irrupt, flare up, flare, break open, burst out -- (erupt or intensify suddenly; "Unrest erupted in the country"; "Tempers flared at the meeting"; "The crowd irrupted into a burst of patriotism")
erupt, belch, extravasate -- (become active and spew forth lava and rocks; "Vesuvius erupts once in a while")
break, burst, erupt -- (force out or release suddenly and often violently something pent up; "break into tears"; "erupt in anger")
erupt -- (appear on the skin; "A rash erupted on her arms after she had touched the exotic plant")
erupt, recrudesce, break out -- (become raw or open; "He broke out in hives"; "My skin breaks out when I eat strawberries"; "Such boils tend to recrudesce")